So-called "video-on-demand" systems have become increasingly popular in a number of applications which include distributing pay-per-view movies in hotels, providing interactive information at kiosks in shopping malls, informing and entertaining patients in hospitals, providing in-flight entertainment on major airlines and training at schools and businesses. The available "video server" technology, however, has severely limited the implementation of these and other potential applications for video-on-demand due to the size and cost of the necessary equipment and the minimal end-user controls.
A typical application of video-on-demand is within the hospitality industry where guests are provided with pay-per-view services. The typical systems which provide these services rely upon large banks of analog video cassette records (VCRs) and associated video cassette tapes queued to pre-scheduled times. The drawbacks of these tape-based, analog systems are the need to provide security for the tapes; manual handling and loading of the tapes; extensive system maintenance; and the high cost of operation. In addition, many customers have to wait for the scheduled times to see the movie of their choice. Further, video tapes degrade each time they are played and eventually must be replaced to maintain clarity and quality.
In contrast with video tape systems, hard disk drives provide video retrieval on demand without the picture degradation imposed by the analog video cassette tapes. Current hard disk based video-on-demand systems, however, suffer many of the other limitations of tape-based systems, such as size, cost and high power consumption. These limitations are the outgrowth of large banks of disk drives utilized to store audio and video in a compressed digital format and associated large banks of processing electronics required to decompress and encode this digital audio and video data into standard analog outputs. These disk-based systems are not modular or easily expandable, and, in addition, typically require the removal of these banks of disk drives in order to install new video programming. Thus, current hard disk systems, like tape-based systems are impractical for many video-on-demand applications.